Process for producing enamels and glazes



Patented Dec. 8,1925.

UNITED STATES PATENT orrics.

FRITZ SOMMER, F BERLIN-CHARLOTTENBURG, AND MAX GROTH, OF BERLIN- ORANIENBURG, GERMANY, ASSIGNORS TO THE FIRM GHEMISCHE -WERKE VOR- MALS'AUERGESELLSCHAFT H. KOMMANDITGESELLSCHAFT, OF BERLIN, GER- MANY, A CORPORATION OF GERMANY.

PROCESS FOR PRODUCING ENAMEL AND GLAZES.

No Drawing.

To all whom it may concern:

Be it known. that we, Fnrrz SoMnnn and MAxGRo'rH, both citizens of the German Empire, residing at Berlin-Charlottenburg, Germany, and Berlin-Oranicnburg, Germany, respectively, have in \-'ented-certain new and useful Improvements in Processes for Producing Enamels and Glazes, of which thefollowing'is a specification.

This invention has reference to the elimination of the s'b-called blistering or bubbling phenomenon occurring in the heating of variousenameling or glazing compositions andit is intended to devise means of producing a glaze or enamel which is free from that'objectionable quality and to generallyimprove and perfect the manufacture of compositions of the kind referred to.

The utilization of a great number of otherwise very satisfactory opacifiers for glazes or enamels or the like'is greatly interfered with by the said phenomenon which the compositions referred to produce upon subsequent firing Various attempts to 55 overcome this drawback heretofore made have not been successful;

In accordance with this inventiom-however, it has been ascertained that certain substances,.such as burnt clay and similar substances ifadded to the opacifiers in the grinding mill will increase the opacity and willprevent the very noxious inconvenience of blistering or bubbling of the composition,"i f these additions before being employed are submitted to a moderately high firing temperature below 1000 degrees centi' gr'adeQ The favorable action of such ad ditions becomes particularly noticeable when using zirconium-oxide for the purpose of 40 producing the opacity but the invention-is by no means restricted thereto.

In carrying out the process of this in- I vention the burnt clay or kaolin with the other ingredients, such as unburnt clay, kaolin, and the like are preferably added to the glazing or enameling composition in the grinding mill for instance. It is obvious, however, that this invention is not restricted to any particular form of execution and. embodiment, but it is susceptible of Various changes and modifications to suitv Application filed May 17, 1 923. Serial No. 639,714.-

existing conditions without di iyiating from the spirit of the invention, as'pointed' out in the claims, and it should be pnderstood that it is not confined to any particulai opacity producing oxide or compofund, and

that instead of clay any suitable argillaceous or clay containing ingredients maybe used.

It is customary in preparing enamels to grind them with clay, and notover") 12 percent, but usually with (3 to 8 percentyunburnt clay. It is this clay that we substitute partially by moderately burnt clay, and the quantity of burnt clay substituted cannot be fixed, as'this will vary according to the heat, the composition of the enamel and theeifect to be produced, but it may amount to more or less than half the unburntclay.

quantity of moderately burnt clay.

3. The process of improving enamels or glazes containing zirconium compounds and un-burnt clay, which comprises incorporating with the compounds in the enamel or glaze a quantity. of moderately burnt argillaceous material. a

4. The process of improvingenamels or glazes which comprises burning an argilla ceous compound at a temperature below 1000 C., and grinding therewith a zirconium compound, a flux and unburnt clay.

5. An enameling or glazing composition containing unburnt and moderately burnt clay. V

6. An enameling and glazing compound containing. an opacity compound, a flux, unburnt clay and moderately burnt clay.

In testimony whereof we afiix our signatures.

DR. FRITZ SUMMER. MAX GROTH. 

